Locking device



July 15, 1947.

o. J. POUPITCH 2,424,208

LOCKING DEVICE Filed Aug. 28, 1944 2 Sheets-Sheet l IN V EN TOR.

July 15, 1947. Q POUPITCH 2,424,208

Filed Aug. 28, ,1944 2 S Patented July 15, 1947 LOCKIN G DEVICE.

OugljesaJuls Poupitch, Chicago, Ill., assignmto Illinois TboPWorks, Chicago; I112; 3;001'1301'37- tion to Illinois Application August 28, 1944,: Serial Not 551,460

7 Claims. 1.

The present invention relates generally. to locking devices for screws and nuts, andfmore particularly to lock washers adapted to. be used with nuts and screw heads having relatively narrow clamping surfaces.

It'is well known that certain typesof'nuts and certain types of screw heads present arelae tively narrow, annular clamping surface to..th'e work. For example, nuts constructed 'in accord ance with S. A. E. standards have a clamping surface and'consequently, an external diameter which is considerably smaller than the clamping surface and external diameter of'the conventional nut. Likewise certain screwheads, such; as filister head screws, .are also relatively small in external diameter andiconsequentlyhaverelatively narrow annular clamping surfaces. The present invention is concerned with the problem of supplying lockwashers, particularly designed to meet the aforesaid dimensional requirementsi It has been found difiicult, for example, to obtain the desired locking efliciency by using available. external tooth or pron'ged lock washers beneath the relatively narrow clamping surfaces of S. A.-E. nuts. This has been clue to the fact that the annular body portion which is usually. positioned in a plane coincident with the plane of the washer. teeth; requires a. considerable radial area, and hence the external teeth of the washer project a considerable distance beyond the external. limits of the clamping surface. To avoid this di'f-. ficulty, lock washers with internal locking teeth'. have been employed; However, in order to maintain maximum locking efficiency it is desirable to have the teeth of the lock washers biteinto the clamping surface 'of the nut in the vicinity. of the outer margin thereof. External teeth .in a lock washer are designed to engage the .clamp-.-- ing surface in the vicinity of its outer margin, but in instances where the clampingsurfaceis relatively narrow it .has not been found practical. to employ external tooth washers becausetheouter extremities'of the washer teethdo. not lockingly engage the clamping surfaceof the nut. In other words, the external diameterv of. the lock washer exceeds by a considerable amount the external diameter of the nut. If theradial. width of a conventional externally, toothed llOCk. washer is reduced'the strength of the lockwasher is seriously impaired. Hence inorder to obtain maximum locking efliciency not only must the locking teeth 'be properly presented to the clamp,- ing surface, but'the annular body supporting said teeth must be of sufficient siz'eto. withstandthe stresses "to which the teeth are subjected; It:

is an object 'offthe present invention .to overcome the. aforesaid. and other structuraland. functio'nal deficiencies by providing a lock Washer havinga maximum body strength andfmaximum toothlengagement with minimum overall or ex-.

ternal flockwasher diameter. To this endIth'e invention contemplates the provisionioffa body portion the entire portion of which extendsnormal toith'e plane of the external 'lock' washer teeth...

Morespecifically, the invention contemplates a..-1ock'..wash'er. as setforth above, wherein locking teeth extend radially outward from one extremity of. anflannular, axially. extending body,- so. that th eaentireouter orradially extendingarea ofthe washer. stock is. employedfor thelockingteeth andithe. entire axially. extending annular. portion isyemplo'yedrfor body strength. rating imanner theexternal'diameterof the lock washer ismaintained nat a..minimum .without sacrificin radial extent of the washer teeth, and without impairing the strength" of the Washer body.

It' is a further. object of the presentinvention to provide fastener devices in which'alock-washer of thettyperefe'rred to above forms the locking structure. andv a nut. having. a. relatively narrowclamping surface forms the other structure; the lockiwasher being. preferably. heldras v-a unit by frictional engagement of 'the axialbody-portion witha complementarywall portion at the clamping'sid .of the nut Itisafurtherobject of the present invention to provideafastener. device wherein the-lock-washerasrspecified above is usedin association with the clamping side ofascrew headvhaving-a relatively narrowclamping surface, such .for example=as the clamping surface of a. filister head. screw, the lo'ck'fwasherbeing preferably-secured as a unit adjacent the clamping surface of the screw head:

The.foregoingaandiother objects and advantageswilllbe moreapparent from thetfollowingdetaileddescription when considered in=connection with the accompanying drawings, wherein:

Figure -1.is aside elevationalview of: alock washer constructedin accordancewith. the teach'-' ings. of. the present invention; V V

Figure 2Tis a-vertical sectional :view taken centrallyof the lock washer. shown. inFigure 1-5 Figure 31 is. a. p1an=view-ot the lockewasher sh'ownin FiguresJandJZ; I

Figure .4 is a sectional. view of thelockwasher as. shown in Figure. 2; the lock-washer being; idisclosed inoperative association-with amut having a relatively narrow clamping; surface;

Figure-5 discloses the loclc washer of Figures 1 body portion. In the disclosed embodiment the lock washer teeth or prongs are tapered, said teeth being wider at their roots than at their outer or free extremities. If sufiicient radial length or extent is provided, these tapered teeth may be progressively twisted from the root to the free extremity so as to present biting edges on opposite sides o'fthe medial plane of the prongs. The present invention provides radially extending stock of sufficient radial width to assure the proper twisting of the teeth from the root to the outer strutting extremity, and at the same time with a filister head screw in which an annular recess or depression at the clamping side of the screw head is provided to accommodate. the axially extending body portion of the lock washer;

Figure 10 is a plan view of a lock washer similar to the lock washer shown in Figures 1 to 3 inclusive, which is designed to be sprung into the cavity on the clamping side of a nut; and

Figure 11 is a fragmentary sectional view, similar to Figure 5, disclosing the manner in which the axial body portion of the lock washer serves as a strengthening bushing to reinforce stock in the vicinity of a hole in the work piece against sheer stresses.

Referring now to the drawings more detail, wherein like numerals have been employed to designate similar parts throughout the various figures, it will be seen that the present invention contemplates a lock washer designated generally by the numeral l2, Figures 1 to 3 inclusive. The lock washer [2 includes an annular, axially extending body portion 14. It will be noted that this body portion I4 is in the nature of a cylindrical flange extending laterally of a plurality of radial locking prongs or teeth l6. By having the entire body section or portion l4 formed cylindrical, or in other words extending laterally with respect to the washer teeth, the entire outer radial portion indicated by the bracket A, Figure 2, is employed for locking purposes.

It will be noted that the radial portion A isof sufficient radial extent to permit the formation of the circumferentially spaced, radially extending locking teeth [6. In the disclosed embodiment these teeth or prongs have their bases next adjacent the lower margin of the axial body l4, Figures 2 and 3. No part of the radial portion A is employed for the washer body and each'tooth is twisted from its base to its outer extremity so as l to provide a plurality of locking edges l6a. These edges l6a are designed to make a line bite with the clamping surface of a nut l8 on one side, and the surface of a work piece on the opposite side, as clearly illustrated in Figure 7. It will be apparent that the axial disposition of the washer body not only enables the entire radial area A to be used for forming locking teeth but also makes it possible to hold to a minimum the external diameterof the lock washer taken across the teeth.

As illustrated in Figure 4, the aforesaid reduction in external diameter makes it possible to retain the entire locking section of the washer, namely the biting edges liia, within the confines of the annular clamping surface of the nutwithout sacrificing body strength and without sacrificing radial extent of the washer prongs. The teeth or prongs I 6, in order to afford maximum locking efficiency, must have sumcient radial length to permit twisting fromtheir roots to their outer extremities without the potential hazard'of fra'cture at the point where the prongs join with the makes it possible to bring the entire group of looking or biting edges into operative association at all' times with the relatively narrow clamping surface of the nut.

It will be apparent that by having a lock washer constructed as described, screw heads with relatively narrow clamping surfaces may be more efficiently locked by externally pronged washers. Furthermore the novel arrangement of the axial body and radial teeth extending from one margin thereof, avoids the unsightly appearance of lock washer teeth or prongs projecting beyond the external margin or periphery of a nut. There are many applications which have heretofore prohibited the use of externally pronged lock washers with nuts having relatively narrow clamping surfaces. The use of externally pronged lock washers in household appliances and the like which must be frequently cleaned or dusted has in many instances been prohibited because of the presence of the sharp, outwardly projecting Washer teeth. The present invention provides a lock washer, the external teeth of which may be held within the confines of the nut periphery, thereby affording maximum locking effectiveness and freedom from exposed locking tooth extremities. There are instances also wherein nuts of the type contemplated hereby must be used in places which because of certain dimensional limitations will not permit the application of a lock washer projecting beyond the confines of the nut periphery.

' Thus far, the lock washer of the present invention has been described as applied to nuts having relatively narrow clamping surfaces. The lock washer also has a very practical application to screws having heads of relatively narrow dimension, such, for example, as filister head screws. In Figure 5 the lock washer I2 is disclosed in operative association with a filister head screw designated generally by the numeral 22, Figures 5 and 8. .The head 24 of the screw 22 has a relatively narrow clamping surface. In the disclosed embodiment the lock washer and screw are telescopically associated prior to the rolling of the thread convolutions 26 thereon. That is to say, the screw blank and lock washer are first telescopically associated and then the thread convolutions 26 are rolled upon the blank. This causes the external diameter of the threaded shank to be enlarged sufliciently to prevent the lock washer from being axially displaced. The combined screw 22 and lock washer l2 provide a fastener unit in which the teeth or prongs l6 are positioned to lock'along the annular area determined by the clamping surface of the screw head. The external'diameter of the lock washer being held to a. minimum, as previously pointed out in connection with'the nut 18, makes it possible to hold the washer teeth within theconfines of the clamping surface of the filister head as illustrated in Figuresf 5' and 8, In addition, the axially extending 1 body [4 of the lock washer provides sufficient tively prevent inadvertent unscrewing of. the lock the fact that in certain sizes of lock washers the stock is relatively thin as compared to the axial pitch of the screw thread. The axial body portion l4 provides sufiicient axial thickness in this vicinity to positively preclude inadvertent separation of the two parts.

In Figure 9 a slightly modified fastener. unit, employing a filister head screw 22a: is shown. This screw 22a has a head 24a which is provided with an annular recess 28 in the vicinity of the clamping surface thereofto accommodate the axial body portion I 4 of the lock washer. The thread convolutions 26a of the screw, like the threaded convolutions 26 previously described, are rolled on the screw blank after'initial telescopic association of the screw and washer. Thus the thread convolutions project sufilciently beyond the internal wall of the body portion l4 so as to secure the lock washer against displacement. By having the axial body portion l4 extend outwardly into the confines of the screw head, the thread convolutions 26a may be rolled closer to the clamping surface of the screw head than the thread convolutions 26. This proves to be advantageous in instances where little or no clearance is provided in the work piece against which the lock Washer is clamped. When the structure shown in Figures and '8 is employed,

sufficient clearance in the work piece must be provided for the portion of the axial body extending laterally from one side of the lock washer. In Figure 9 this structural requirement is avoided.

Attention is directed to a slight clearance, indicated by the numeral 30 in Figure 4 and 32 of Figure 9, between the edge of the body portion l4 and the adjacent portion of the screw head. When the nut of Figure 4 is tightened against the work piece 2!), as illustrated in Figure 7, the clearance 30 is taken up due to the slight untwisting of the lock washer teeth. By having direct bearing between the screw head and the inner edge of the axial body l4 after the nut has been tightened in place, further tendency for the lock washer teeth to untwist or become flattened is effectively counteracted. Likewise the clearance 32 is taken up. during theinitial tightening of the filister head 24a againstia work piece.

In Figure a slightly modified lock washer structure is shown. This lock washer is designated generally by the numeral |2a and is similar in every respect to the lock washer I2 except that the body 14 is severed at 34. The lock washer He must be slightly collapsed before association with the nut l8. After the axial body of the washer l 2a has been positioned within the recess of the nut, the washer is released and the axial body thereof springs outwardly into frictional contact with the complementary wall of the nut. In this way the lock washer is held by spring pressure as a unit within the nut. In instances where this resilient retention of the lock washer within the nut is not required, the annularly continuous body portion M, as shown in Figures 1 to 3 inclusive, may be forced into a frictional fit within the confines of the nut recess so as to present a preassembled nut and lock washer provide device. It wilithu be apparenhthat;thelprcvia sion ofthe axialbqcly portion, facilitates. preassembly 0f:the nutandlock washer, .both with respectto nuts and screws.

In Figure ll the filister headiscrew, andassociated lockwasher; are. shown; in, operative a'ssociation with a work piecetl and a sheet metal workpiece 35. The work piece. 34.;isthreaded; and the sheet metalwork piece 36 ;is.,ap.ertured to accommodate the screw, 22. Itwillbe. noted.

that the cylindricalbody portionor flange. IAuOf the lock washer l2. provides; a reinforcement within the aperture of thesheet metal work piece. 36.v In this mannerthe axial'body.portion/serves as a reinforcement against sheer stress.

Summarizing, the present, invention provides a lock washer construction which is particularly. adaptable for use with relativelynarrow rotary; clamping surfacesofthreadedfasteners, such, for instance, as nuts and screws, By having. the. entire axial portion of the lock. washer stock. available fora body portion, the.externa'l,diame-.

ter is reduced to a minimum without the slightest impairment of-the locking effectiveness ofthe teeth. The invention has made it possible-to preassembled nuts and toothed lock Washers in which the teeth of the lock washer are maintained within the. area de'-. fined by the clamping surface of. th nut. Like wise, the invention has made possible the pro.-.

duction of a screw and lockwasher assemblywherein the clamping surface. of the screw headis relatively narrow, the lock'washer beingso designed as to positively preclude inadvertent or unauthorized unscrewingof. the parts The lock washer of the present invention may be -manufactured with the utmost of economy and by the practice of conventional stamping and forming methods.

Obviously the invention is notlimited to the specific structural details disclosed. herein, but is capable of other modifications and changes without departing from the spiritand scope of the:

appended claims.

I claim:

1. A look. washer including aninternal axially extending, annular body portion, and a plurality of locking teeth extending radially outward froma peripheral margin ofsaid body portionand axiallyoutwardly beyond the plane of an end margin of said body portion, said body portion being ingside of a rotary threaded fastener whereby to reduceto a minimum. the externaldiameters-of the lock washer without sacrificing lock-ing effectiveness.

2. A lock washer includin an internal annular, axially extending body portion, and a plurality of locking prongs extending radially outward from one margin of said body portion, each prong presenting locking edge positioned on opposite sides of the median plane of said prongs, one locking edge of each prong projecting outwardly beyond the plane of an end margin of the body portion, said annular body portion providing a substantially cylindrical flange extending laterally from the base of said washer teeth a sufiicient axia1 distance to provide washer retention means for the clamping side of a rotary threaded fastener whereby to reduce to a minimum the outer diameter of the lock washer without sacrificing locking efiectiveness.

3. A look washer including an annular, axially externally extending internalbody portion, said body portion being resiliently shiftable transversely of the washer axis to permit telescopic preassembly with a complementary threaded fastener, and a plurality of locking teeth extending radially outward from one margin of said body portion and axially outward beyond the plane of an end margin of said body portion, the body portion providing a flange extending laterally from the base of said washer teeth-a sufficient axial distance to provide washer retention means for the clamping side of a rotary threaded fastener whereby to reduce to a minimum the outer diameter of the lock washer without sacrificing locking efiectiveness.

4. A locking device including a substantially cylindrical, axially extending washer body, a plurality of locking teeth extending radially outward from one margin of said washer body, and a rotary threaded fastener associated as a unit therewith having an annular relatively narrow clamping surface, said locking teeth being positioned adjacent said clamping surface and extending radially of the fastener substantially from an inner margin of said surface to, but not beyond, the outer margin of said surface, and the washer body portion providing a flange extending laterially from the base of the washer teeth, said flange body in adjacent encircling relation in respect to the threaded fastener and having a suflicient axial length to provide Washer retention means for the clamping side of said rotary threaded fastener whereby to reduce the outer diameter of the lock washer and thereby position the washer teeth in proper locking relation with respect to said relatively narrow clamping surface.

5. A locking device including an annular, cylindrical washer body, a plurality of locking teeth extending radially outward from a peripheral margin of said washer body and axially outwardly beyond the plane of an'end margin of said body, and a rotary threaded fastener associated therewith as a unit having an annular relatively narrow clamping surface, said 'locking teeth being positioned adjacent said clamping surface and the Washer body portion providing a flange extending laterally from the base of the washer teeth a sufiicient axial distance'to provide washer retention means for the clamping side of said rotary threaded fastener whereby to reduce the outer diameter of the lock washer and thereby position the washer teeth in proper locking relation with respect to said relatively narrow I ping surface.

ripheral margin of said body and axially outward from an end margin of said body, said body being of sufficient axial length to provide washer retention means, and a threaded fastener associated therewith as a unit having a relatively narrow annular clamping surface, said fastener having a recess extending axially inward from said clamping surface providing an annular axially extending wall to accommodate said axially extending washer body, the entire radially extending portion of the washer comprising the aforesaid radial locking teeth, said washer body being frictionally secured as a unit with said fastener.

7. A locking device including an annular, axially extending washer body, a plurality of looking prongs extending radially outward from the outer peripheral margin of said body and axially beyond the end margin of said body, and a screw member associated therewith as a'unit comprising a threaded shank and a head at one extremity thereof presenting a relatively narrow annular clamping surface, said screw member having an unthreaded washer receiving portion adjacent said clamping surface, the diameter of said unthreaded portion and the internal diameter of said annular washer body being less than the external diameter of said threaded shank, said lock washer being secured in operative position adjacent said clamping surface, the washer body being disposed in adjacent encircling relation with respect to the unthreaded portion of the screw shank and extending axially of the screw member a suflicient distance to provide washer retention means with the Washer prongs disposed in locking relation with respect to the clamping surface.

OUGLJESA JULES POUPITCH.

REFERENCES CITED The following references are of record in the file of this patent:

I *UNITED STATES PATENTS Number Name Date 2,225,654 Olson (a) Dec. 24, 1940 1,030,136 Skelton June 18, 1912 1,561,880 Morrison Nov. 1'7, 1925 1,643,384 Klafke Sept. 27, 1927 2,112,425 Crowther .Apr. 5, 1938 1,924,695 Olson (b) Aug. 29, 1933 1,645,859 Hosking Oct. 18, 1927 FOREIGN PATENTS Number Country Date 540,864 Great Britain Nov, 3, 1941 110,337 Switzerland Aug. 1, 1925 

